Ulva sp. and Chaetomorpha sp. - photoperiods

[Keith_Man]

I haven't been able to find much literature on macro algae photoperiods but what is the optimum photoperiod for both Ulva sp. and Chaetomorpha sp.? can these algaes grow under 24hour lighting?

Is it true that Caulerpa is the only Macro Algae that does not need a dark cycle?

Thanks in advance

Keith

[Reef This]

I hang around this forum alot lookign for people with answers to my Chaeto problem. To no avail, however. I've seen 12 hours, 10 hours, 24 hours, one day on, one off, all kinda of different photoperiods for getting Chaeto to grow.

None of them work for me, the stuff refuses to grow in my system. =/

[Keith_Man]

yes, i've also found a very mixed response to growing cheato. It is my understanding that Chaeto needs a dark cycle in order to convert ATP which i created in the light cycle into glucose, much like terrestial plants. Can anyone confirm if this is correct?

Reef this, How are you trying to grow your cheato? is it in a mud fuge? It could be possible that Chaeto is not receiving enough nutrients or the correct elements to grow eg, Iron. Just a stab in the dark

any further comments on 24hr lighting would be great appreciated

Thanks

Keith

[billsreef]

Just to confuse you guy's, I've grown both Cheat and Ulva under 24 hour photoperiods as well as 12/12. The only time I've found shorter than 24hr periods to improve growth is when there are diatom problems in the system that seem. If you have problems with diatoms covering your macro's, than simply adding a dark period will favour the macro growth ;) I also find that the 24 hr photoperiod does not significantly increase the growth rates of these macro's if the nutrient inputs are limited. So essentially, unless your tank has huge nutrient inputs, the 24hr photoperiod is likely to do nothing but increase your electric bill ;)

[Keith_Man]

Thanks billsreef!

Do you know of a scientific reason why these algae do not need a dark period?

[billsreef]

I don't have any good references handy for you. But it is my understanding that the "dark" reactions are still taking place in the daylight hours as well. Hence the dark isn't truly necessary. It's more that the plants have evolved to be able to produce excess during the day that can then be worked on at night as well.

[Keith_Man]

Thanks again! much appreciated